Advocate staff photo by MATTHEW HINTON--U.S. Sen. Mary Landrieu, D-La., speaks at the Hyatt Regency New Orleans about the election Senate election results in her contest with U.S. Rep. Bill Cassidy, R-La., and Tea Party candidate Rob Maness in New Orleans, La. Tuesday, Nov. 4, 2014.

Conservative activist James O’Keefe claims he has gone undercover at U.S. Sen. Mary Landrieu's campaign headquarters and says he has a "big story" to tell ahead of the Dec. 6 run off vs. U.S. Rep. Bill Cassidy.

O'Keefe is known for these kinds of projects, which are usually intended to embarass liberals.

O’Keefe and three others were arrested in 2010 after they snuck into Landrieu’s office under the guise of being telephone repairmen. Authorities claimed the four were trying to tamper with Landrieu’s office phones.

Check out more details on O'Keefe's visit to Landrieu's camp on our politics blog.